1. Field of the Invention
The present invention relates to a reproducing device which is suitably used for disc-shaped recording media such as CD-DA which is a so-called digital audio compact disc, a video CD, etc.
2. Description of the Related Art
Various read only memory type disc media (used exclusively for reproduction) such as CD-DA, video CD, etc. have propagated in the market. The CD-DA is designed so that an user can record digital audio data of pieces of music, etc. thereon and then reproduce the recorded data to enjoy these pieces of music with high sound quality. In addition, as a derivative of the CD-DA has been known CD-G (so-called CD-Graphics) in which still image data are recorded in a sub code data.
Furthermore, there has been also developed a video CD which is based on a format of the CD-ROM and in which video data as well as digital audio data are recorded.
In the various discs as described above, audio information or video information is recorded on a program basis (i.e., a recording unit of these information corresponds to a program). For example, in the case of a CD-DA having ten pieces of music, each piece of music corresponds to a program, and in this sense ten programs are regarded as being recorded on the CD-DA. The same is applied to the video CD. For example, in the case of a video CD having ten, chapters, each chapter corresponds to a program, and thus ten chapters are recorded on the video CD.
Furthermore, when a disc producer wants to subdivide a program, he can add index information to the disc. With respect to the CD-DA, index information is added every program, and thus reproduction can be performed from any index number of any program number through an user's index access operation. In the CD-DA, the number of index information pieces of respective parts to which the program is subdivided is recorded, however, address information of each subdivided index point is not recorded.
When an index access is instructed, it must be checked at a reproducing device side whether there is any index-number varying point in a program which is being produced when the index access is instructed, in order to search the head of the index point.
The above search operation needs a long time, and thus there is a disadvantage that a desired index point cannot be rapidly accessed.
In the case of the video CD, an user may also access an index point in a desired chapter by adding index information, for example, when a long reproduction time is needed For a chapter because video information is a movie or the like. In order to enable this operation, an address point called as "entry address" is recorded every chapter, and then it is used as index information to perform a reproducing operation from a desired index number of a desired chapter.
The index information is preset in accordance with intention of a disc producer, and thus a number of discs having no index information are actually put on the market.
As described above, if index information is preset in a disc, an user can readily start reproduction of his desired program even from a middle portion of the program. However, if no index information is preset in the disc, he must advance the frames of a picture by actuating a cue/review (quickly reproducing operation) key or the like to start the reproduction of his desired program from a middle portion thereof. In order to perform the quickly reproducing operation, the user must continue to push an operation button until his desired frame appears. Therefore, this has been a remarkably unfavorable operation in usability and visibility.